Refrigerating machine including an economizer



Jan. 19, 1965 c. D. WARE REFRIGERATING MACHINE INCLUDING AN ECONOMIZER 2 Sheets Sheec, 1

Filed Aug. 15, 1962 INVENTOR.

C H E S TER D. WA R E A T T O R N F Y S C. D. WARE REFRIGERATING MACHINE INCLUDING AN ECONOMIZER Jan. 19, 1965 Filed Aug. 15, 1962 2 Sheets-Sheet 2 INVENTOR.

CHE$ TE R 0. WA R E v QMM A T T O R N E Y S United. rates Patent Office 3,165,965 Patented Jan. 19., 1965 Chester D. Ware, La Crosse, Wis., assignor to The Trane Company, La Crosse, Wis. Filed Aug. 15, 1962, Ser. No. 217,986

9 Claims. (Cl. 62-419) This invention relates to refrigerating apparatus of the type including a motor-compressor assembly and particularly to apparatus in which the motor and two compressors are housed in a sealed unit.

It is an object of this invention to provide improved means for cooling the motor of refrigerating apparatus using liquid refrigerant from the economizer of the apparatus as a heat exchange medium.

It is another object of this invention to provide an economizer flash chamber separate from or within the casing which encloses the motor and compressors and to provide means for conducting refrigerant liquid from the casing to the evaporator only when the liquid refrigerant in the casing is above a predetermined level.

It is another object of thisrinvention to conduct liquid refrigerant to passageways of the motor stator to cool the motor by evaporation of refrigerant and to provide means for conducting the vaporized refrigerant to the inlet of the second stage compressor.

It is still another object of the invention to circulate vapor within the motor chamber to transfer heat from hot parts of the motor to the cooled parts of the motor.

Other objects and advantages of the invention will appear as the specification proceeds to describe the invention with reference to the accompanying drawings in which:

FIGURE 1 is a partly diagrammatic view of the refrigerating apparatus with portions sectioned to more clearly show the interior construction;

FIGURE 2 is a cross-sectional view taken on line 2-2 of FIGURE 1;

FIGURE 3 is an enlarged sectional View taken on an axial plane through one of the stator supporting bars and showing a portion of the interior of the motor; and

FIGURE 4 is a partly diagrammatic view of a modification of the refrigerating apparatus with portions sectioned to more clearly show the interior construction.

Referring now to FIGURE 1, an electric motor has at one end a first stage compressor 12 and at the other end a second stage compressor 14. A cross-over pipe 16 conducts gas from the discharge of the first stage compressor 12 to the inlet of the second stage compressor 14.

The gas from the second stage compressor 14 flows through conduit 18 to a condenser 20. The condenser 20 may be of the shell and-tube type in which cooling water flows through the tubing 22 and the refrigerant is in the shell outside the tubes. Refrigerant liquid condensed in the condenser 20 flows by gravity through conduit 23 to a float valve 24 which opens when the liquid in the valve is above a predetermined level. The refrigerant liquid and flashed refrigerant vapor flows from float valve 24 through conduit 26 to an economizer chamber 27.

The motor 10 has [a fluid tight casing 36 secured in fluid sealing relationship to the housings of the compressors 12 and 14. Bars 37 are secured to the casing 36 and to a motor stator 38 to support the motor stator 38 in the casing 36. As more clearly shown in FIGURE 3, the stator 38 comprises large diameter larninations 43 and smaller diameter laminations 44 thus providing annular passageways 45 between the stator 38 and the casing 36 for the flow of refrigerant. The refrigerant flowing in annular passageways 45 contacts and cools large surface areas of the stator 38, the bars 37 and the casing 36. Rings 40 and 41 are secured to the casing 36 to provide additional support for the stator 38 and bars 37, and to seal the annular spaces 45 from the interior of the motor.

A shaft 48 is rotatably supported in the casing 36 by bearings (not shown) and extends at one end into compressor 12 and has centrifugal impeller 52 secured thereto. The other end of shaft 48 extends into compressor 14 and has impeller 54 secured thereto. A motor rotor 56 is secured to the shaft 48 and has fan blades 58 for circulating the refrigerant vapor over the surfaces of the shaft 48, the rotor 56, and the ends of the stator windings 59. This circulation of refrigerant vapor transfers heat from these parts to the cooled parts of the motor.

The refrigerant vapor flashed from the liquid in the economizer and the vapor generated by the heat from the motor flows through a liquid eliminator 60 and thence through a conduit 62 to the cross-over pipe 16.

An overflow conduit 64 conducts refrigerant liquid from motor casing 36 to a float valve 66 when the liquid level in motor casing 36 is sufficiently high to flow into conduit 64. Float valve 66 opens when the liquid is above a predetermined level in the valve. From the float valve 47 the liquid refrigerant flows through conduit 68 to an evaporator 70.

Evaporator 70 may be of the shell-and-tube type in which secondary refrigerant such as water or brine flows through the tubing 72 and the refrigerant is in the shell outside the tubing 72. The secondary refrigerant liquid circulates between the evaporator 70 and the cooling load served by the refrigeration apparatus to transfer heat from the load to the evaporator '70. In removing heat from the secondary refrigerant, the refrigerant in the evaporator 71) boils forming vapor which passes through the liquid eliminator 74 into the suction pipe 76 to the inlet of the first stage compressor 12. The compressed refrigerant vapor flows from the discharge of compressor 12 through cross-over pipe 16 to the inlet of second stage compressor 14.

Under certain temperature conditions which might occur after a shut down of the apparatus, there can be a situation where there is little or no liquid refrigerant in the casing 36 for cooling the motor 10. When the machine is started under such conditions, all of the re frigerant liquid produced by the apparatus flows through conduit 26 to the casing 36 to cool the motor 10 by vaporization of the refrigerant liquid. Refrigerant liquid does not flow through overflow conduit 64 until the refrigerant liquid rises to the level of conduit 64. I prefer to have conduit 64 substantially at the level shown in FIGURE 1 in order to have the stator 36 substantially submerged in liquid, thus providing very effective cooling of the motor. However, the conduit 64 may be located at a lower level in machines which do not require as much motor cooling capacity.

Referring now to FIGURE 4 which shows a modification of the apparatus of FIGURE 1 and in which corresponding parts have like numerals, the refrigerant liquid flows from the condenser 20 through conduit 78 to a float valve 86 which maintains a liquid level in the 88 to a float valve 66 which maintains aliquid level in.

the float valve chamber. Conduit 68 conducts refrigerant liquid and flash gas to evaporator '70.

The operation of the apparatus of FIGURE 4 is similar to that of FIGURE 1 in that on initiating operation, the refrigerant liquid first produced by the condenser flows directly through conduit 83 to the lower portion of the motor casing 36 for motor cooling. Refrigerant liquid does not flow through conduit 9?. until the liquid in conduit 88 rises to the outlet to conduit 92. At this condition, the refrigerant liquid in the casing is substantially at the same level as the refrigerant iiquid in conduit 83 and the desired effective motor cooh'ng is obtained as explained more fully with reference to FIGURE 1.

While I have described the foregoing preferred embodiments of my invention, I contemplate that many changes may be made without departing from the scope or spirit of my invention and I desire to be limited only by the.

claims.

I claim:

1. A refrigerating machine comprising:

(a) an evaporator,

(b) a condenser,

(c) a first stage compressor,

(d) means for conducting refrigerant vapor from said evaporator to said first stage compressor,

(e) a second stage compressor,

(1) first conduit for conducting compressed refrigerant vapor from the discharge of said first stage compressor to the inlet of said second stage compressor,

(g) second conduit for conducting the compressed refrigerant from the discharge of said second stage compressor to said condenser,

(h) a casing,

(i) an electric motor stator mounted in-said casing,

(j) means providing an annular passageway between said electric motor stator and said casing,

(k) a rotor and shaft assembly rotatably mounted in said casing,

(l) impellers mounted on said rotor and shaft assembly and operating in said first stage compressor and said second stage compressor,

(m) an economizer chamber,

(a) third conduit for conducting refrigerant from said condenser to said economizer chamber,

(0) means in said third conduit for controlling the flow of refrigerant in said third conduit,

( 2) means for conducting refrigerant liquid from said economizer chamber to said casing,

(q) means for conducting refrigerant vapor from said economizer chamber to said first conduit,

(1') means for conducting refrigerant liquid from said economizer chamber to said evaporator when the refrigerant liquid in said casing is above a predetermined level, and

(s) means for conducting refrigerant vapor from said casing to said first conduit.

2. A refrigerating machine comprisin (a) an evaporator,

(12) a condenser,

(c) a first stage compressor,

(d) means for conducting refrigerant vapor from said evaporator to said first stage compressor,

(e) a second stage compressor,

( first conduit for conducting compressed refrigerant vapor from the discharge of said first stage compressor to the inlet of said second stage compressor,

(g) second conduit for conducting the compressed refrigerant from the discharge of said second stage compressor to said condenser,

(11) a casing,

(i) an electric motor stator mounted in said casing and having grooves in its periphery,

(j) means providing an annular passageway between said electric motor stator and said casing,

(k) a rotor and shaft assembly rotatably mounted in said casing,

(l) impellers mounted on said rotor and shaft assembly and operating in said first stage compressor and said second stage compressor,

(in) fan means mounted on said rotor and shaft assembly for circulating refrigerant vapor over said rotor and shaft assembly, said stator and said casing to transfer heat from said shaft and rotor assembly and said stator to said casing,

(n) an economizer chamber,

(0) third conduit for conducting refrigerant from said condenser to said economizer chamber,

(p) means in said third conduit for controlling the flow of refrigerant supplied to said economizer chamber,

(q) means for conducting refrigerant vapor from said economizer chamber to said first conduit,

(r) means for conducting refrigerant liquid from said economizer chamber to said casing,

(s) means for conducting refrigerant vapor from said casing to said first conduit,

(t) means for conducting refrigerant liquid from said economizer chamber to said evaporator only when the refrigerant liquid in said casing is above the centerline of the shaft and rotor assembly.

3. A refrigerating machine comprising:

(a) an evaporator,

(15) a condenser,

(c) a first stage compressor,

(d) means for conducting refrigerant vapor from said evaporator to said first stage compressor,

(2) a second stage compressor,

(f) first conduit for conducting compressed refrigerant vapor from the discharge of said first stage compressor to the inlet of said second stage compressor,

(g) second conduit for conducting the compressed re frigerant from the discharge of said second stage compressor to said condenser,

(ll) a casing,

(i) an electric motor stator mounted in said casing,

(j) means providing an annular passageway between said electric motor stator and said casing,

(k) a rotor and shaft assembly rotatably mounted in said casing,

(l) impellers mounted on said rotor and shaft assembly and operating in said first stage compressor and said second stage compressor,

(m) an economizer chamber,

(11) third conduit for conducting refrigerant from said condenser to said economizer chamber,

(0) means in said third conduit for controlling the flow of refrigerant in said third conduit,

( 1) fourth conduit for conducting refrigerant vapor from said economizer chamber to said first conduit,

(q) means for conducting refrigerant liquid from said economizer chamber to said evaporator when the refrigerant liquid in said casing is above a predetermined level,

(1') conduit connected between said economizer chamher and the lower portion of said casing for conducting refrigerant liquid to said casing, and

(s) means for conducting refrigerant vapor from the upper portion of said casing to said first conduit.

4. A refrigerating machine comprising:

(a) an evaporator,

(b) a condenser,

(c) a first stage compressor,

(d) means for conducting refrigerant vapor from said evaporator to said first stage compressor,

(a) a second stage compressor,

(f) first conduit for conducting compressed refrigerant vapor from the discharge of said first stage compressor to the inlet of said second stage compressor,

(g) second conduit for conducting the compressed refrigerant from the discharge of said second stage compressor to said condenser,

(h) a casing, V

(i) an electric motor stator mounted in said casing and having grooves in its periphery,

(j) means providing an annular passageway between said electric motor stator and said casing,

(k) a rotor and shaft assembly rotatably mounted in said casing,

(l) impellers mounted on said rotor and shaft assembly and operating in said first stage compressor and said second stage compressor,

(m) fan means mounted on said rotor and shaft assembly for circulating refrigerant vapor over said rotor and shaft assembly, said stator and said casing to transfer heat from said shaft and rotor assembly and said stator to said casing,

(12) an economizer chamber in said casing in fluid communication with the annular passageway between said electric motor stator and said casing,

(0) third conduit for conducting refrigerant from said condenser to said economizer chamber,

(p) means in said third conduit for controlling the flow of refrigerant in said third conduit,

(q) fourth conduit for conducting refrigerant vapor from said economizer chamber to said first conduit, and

(r) fifth conduit for conducting refrigerant liquid from said casing to said evaporator, said fifth conduit being constructed and arranged with respect to said casing to conduct refrigerant liquid only when the refrigerant liquid level in said casing is above the centerline of the shaft and rotor assembly.

5. A refrigerating machine Comprising:

(a) an evaporator,

(b) a condenser,

(c) a first stage compressor,

(d) means for conducting refrigerant vapor from said evaporator to said first stage compressor,

(e) a second stage compressor,

(f) first conduit for conducting compressed refrigerant vapor from the discharge of said first stage compressor to the inlet of said second stage compressor,

(g) second conduit for conducting the compressed refrigerant from the discharge of said second stage compressor to said condenser,

(h) a casing, t

(i) an electric motor stator mounted in said casing,

(1') means providing an annular passageway between said electric motor stator and said casing,

(k) a rotor and shaft assembly rotatably mounted in said casing, (l) impellers mounted on said rotor and shaft assembly and operating in said first stage compressor and said second stage compressor,

(m) fan means mounted on said rotor and shaft assem ly for circulating refrigerant vapor over said rotor and shaft assembly, said stator and said casing to transfer heat from said shaft and rotor assembly and said stator to said casing,

(n) an economizer chamber in said casing in fluid communication with the annular passageway between said electric motor stator and said casing,

(0) third conduit for conducting refrigerant from said condenser to said economizer chamber,

(p) means in said third conduit for controlling the flow of refrigerant in said third conduit,

(q) fourth conduit for conducting refrigerant vapor from said economizer chamber to said first conduit, and

(r) fifth conduit for conducting refrigerant liquid from said casing to said evaporator, said fifth conduit being constructed and arranged with respect to said casing to conduct refrigerant liquid only when the refrigerant liquid level in said casing is above the centerline of the shaft and rotor assembly. I

6. A refrigerating machine comprising:

(a) an evaporator,

(b) a condenser,

(c) a first stage compressor,

(d) means for conducting refrigerant vapor from said evaporator to said first stage compressor,

(e) a second stage compressor,

(1) first conduit for conducting compressed refrigerant vapor from the discharge of said first stage compressor to the inlet of said second stage compressor,

(g) second conduit for conducting the compressed refrigerant from the discharge of said second stage compressor to said condenser,

(h) a casing,

(i) an electric motor stator mounted in said casing and having grooves in its periphery,

(j) means providing an annular passageway between said electric motor stator and said casing,

(k) a rotor and shaft assembly rotatably mounted in said casing,

(l) impellers mounted on said rotor 'and'shaf-t assembly and operating in said first stage compressor and said second stage compressor,

(m) an economizer chamber in said casing in fluid communication with the annular passageway between said electric motor stator and said casing,

(n) third conduit for conducting refrigerant from said condenser to said economizer chamber,

(0) means in said third conduit for controlling the flow of refrigerant in said third conduit,

(p) fourth conduit for conducting refrigerant vapor from said economizer chamber to said first conduit, and

(q) fifth conduit for conducting refrigerant liquid from said casing to said evaporator, said fifth conduit being constructed and arranged with respect to said casing to conduct refrigerant liquid only when the refrigerant liquid level in said casing is above the centerline of the shaft and rotor assembly.

7. A refrigerating machine comprising:

(a) an evaporator, i

(b) a condenser,

(c) a first stage compressor,

(d) means for conducting refrigerant vapor from said evaporator to said first stage compressor,

(2) a second stage compressor,

(f) first conduit for conducting compressed refrigerant vapor from the discharge of said first stage compressor to the inlet of said second stage compressor,

(g) second conduit for conducting the compressed refrigerant from the discharge of said second stage compressor to said condenser,

(h) a casing,

(i) an electric motor stator mounted in said casing and having grooves in its periphery,

(1') means providing an annular passageway between said electric motor stator and said casing,

(k) a rotor and shaft assembly rotatably mounted in said casing,

(l) impellers mounted on said rotor and shaft assembly and operating in said first stage compressor and said second stage compressor,

(m) fan means mounted on said rotor and shaft assembly for circulating refrigerant vapor over said rotor and shaft assembly, said stator and said casing to transfer heat from said shaft and rotor assembly and said stator to said casing,

(n) an economizer chamber in said casing in fluid communication with the annular passageway between said motor stator and said casing,

(0) third conduit for conducting refrigerant from said condenser to said economizer chamber,

(p) means in said third conduit for controlling the flow of refrigerant in said third conduit,

(q) fourth conduit for conducting refrigerant vapor from said economizer chamber to said first conduit, and

(r) means for conducting refrigerant liquid from said casing to said evaporator when the refrigerant liquid in said casing is above a predetermined level.

8. A refrigerating machine comprising: 7

(a) an evaporator,

(12) a condenser,

(c) a first stage compressor,

(d) means for conducting refrigerant vapor from said evaporator to said first stage compressor,

(e) a second stage compressor,

(f) first conduit for conducting compressed refrigerant vapor from the discharge of said first stage compressor to the inlet of said second stage compressor,

(g) second conduit for conducting the compressed'refrigerant from the discharge of said second stage compressor to said condenser,

(h) a casing,

(i) an electric motor stator mounted in said casing,

(j) means providing an annular passageway between said electric motor stator and said casing,

(k) a rotor and shaft assembly rotatably mounted in said casing,

(l) impellers mounted on said rotor and shaft assembly and operating in said first stage compressor and said second stage compressor,

(m) an economizer chamber in said casing in fluid communication with the annular passageway between said electric motor stator and said casing,

(n) third conduit for conducting refrigerant from said condenser to said economizer chamber,

() means in said third conduit for controlling the flow of refrigerant in said third conduit,

(p) fourth conduit for conducting refrigerant vapor from said economizer chamber to said first conduit, and I (q) fifth conduit for conducting refrigerant liquid from said casing to said evaporator, said. fifth conduit being constructed and arranged with respect to said casing to conduct refrigerant liquid only when the refrigerant liquid level in said casing is above the centerline of the shaft and rotor assembly.

9. A refrigerating machine comprising:

(a) an evaporator,

(b) a condenser,

(c) a first stage compressor,

(d) means for conducting refrigerant vapor from said evaporator to said first stage compressor,

(e) a second stage compressor,

(1) first conduit for conducting compressed refrigerant vapor from the discharge of said first stage compressor to the inlet of said second stage compressor,

(g) second conduit for conducting the compressed refrigerant from the discharge of said second stage compressor to said condenser,

(12) a casing,

(i) an electric motor stator mounted in said casing,

(1') means providing an annular passageway between said electric motor stator and said casing,

(k) a rotor and shaft assembly rotatab-ly mounted in said casing,

(l) impellers mounted on said rotor and shaft assembly and operating in said first stage compressor and said second stage compressor,

(m) an economizer chamber in said casing in fluid communication with the annular passageway between said electric motor stator and said casing,

(n) third conduit for conducting refrigerant from said condenser to said economizer chamber,

( 0) means in said third conduit for controlling the flow of refrigerant in said third conduit,

(p) fourth conduit for conducting refrigerant vapor from said economizer chamber to said first conduit, and

(q) means for conducting refrigerant from said casing to said evaporator when the refrigerant liquid in said casing is above a predetermined level.

References Cited in the file of this patent UNITED STATES PATENTS 2,746,269 Moody May 22, 1956 2,793,506 Moody May 28, 1957 2,986,905 Kocher June 6, 1961 3,022,638 Caswell Feb. 27, 1962 FOREIGN PATENTS 863,964 Great Britain Mar. 29, 1961 

1. A REFRIGERATING MACHINE COMPRISING: (A) AN EVAPORATOR, (B) A CONDENSER, (C) A FIRST STAGE COMPRESSOR, (D) MEANS FOR CONDUCTING REFRIGERANT VAPOR FROM SAID EVAPORATOR TO SAID FIRST STAGE COMPRESSOR, (E) A SECOND STAGE COMPRESSOR, (F) FIRST CONDUIT FOR CONDUCTING COMPRESSED REFRIGERANT VAPOR FROM THE DISCHARE OF SAID FIRST STAGE COMPRESSOR TO THE INLET OF SAID SECOND STAGE COMPRESSOR, (G) SECOND CONDUIT FOR CONDUCTING THE COMPRESSED REFRIGERANT FROM THE DISCHARGE OF SAID SECOND STAGE COMPRESSOR TO SAID CONDENSER, (H) A CASING, (I) AN ELECTRIC MOTOR STATOR MOUNTED IN SAID CASING, (J) MEANS PROVIDING AN ANNULAR PASSAGEWAY BETWEEN SAID ELECTRIC MOTOR STATOR AND SAID CASING, (K) A ROTOR AND SHAFT ASSEMBLY ROTATABLY MOUNTED IN SAID CASING, 